Matthew 17:10-13 And his disciples asked him, saying, Why then say the scribes that Elijah must first come? And Jesus answered and said unto them, Elijah truly shall first come, and restore all things. But I say unto you, That Elijah is come already, and they knew him not, but have done unto him whatsoever they listed. Likewise shall also the Son of man suffer of them. Then the disciples understood that he spake to them of John the Baptist.

The Spirit of Elijah is the Spirit of Restoration

Elijah shall come and restore all things.

Isaiah 42:22 But this is a people robbed and spoiled; they are all of them snared in holes, and they are hid in prison houses: they are for a prey, and none delivereth; and for a spoil, and none saith, Restore.

Acts 3:19-21 Repent ye therefore, and be converted, that your sins may be blotted out, when the times of refreshing shall come from the presence of the Lord; And he shall send Jesus Christ, which before was preached unto you: Whom the heaven must receive until the times of restitution of all things, which God hath spoken by the mouth of all his holy prophets since the world began.

Joel 2:28-32 And it shall come to pass afterward, that I will pour out my spirit upon all flesh; and your sons and your daughters shall prophesy, and your old men shall dream dreams, and your young men shall see visions: And also upon the servants and upon the handmaids in those days will I pour out my spirit. And I will show wonders in the heavens and in the earth, blood, and fire, and pillars of smoke. The sun shall be turned into darkness, and the moon into blood, before the great and terrible day of the Lord come. And it shall come to pass, that whosoever shall call on the name of the Lord shall be delivered: for in mount Zion and in Jerusalem shall be deliverance, as the Lord hath said, and in the remnant whom the Lord shall call.